postanesthetic shivering l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Postanesthetic Shivering PowerPoint Presentation
Download Presentation
Postanesthetic Shivering

Loading in 2 Seconds...

play fullscreen
1 / 24

Postanesthetic Shivering - PowerPoint PPT Presentation


  • 245 Views
  • Uploaded on

Postanesthetic Shivering. Epidemiology, Pathophysiology, Prevention and Management. Reference. Perioperative Shivering Physiology and Pharmacology Anesthesiology 2002; 96: 467-84 Postanesthetic Shivering Epidemiology, Pathphysiology, and Approaches to Prevention and Management

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Postanesthetic Shivering' - jess


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
postanesthetic shivering

Postanesthetic Shivering

Epidemiology, Pathophysiology, Prevention and Management

Chih-Min Liu

reference
Reference
  • Perioperative Shivering
    • Physiology and Pharmacology
      • Anesthesiology 2002; 96: 467-84
  • Postanesthetic Shivering
    • Epidemiology, Pathphysiology, and Approaches to Prevention and Management
      • Drugs 2001; 61 (15): 2193-2205
  • Clinical Anesthesiology, third edition
    • Chapter 6: Patient monitors; 117-120

Chih-Min Liu

clinical considerations
Clinical Considerations
  • Hypothermia: < 36 oC
  • O2 consumption x 5; decrease saturation; myocardial ischemia and angina
  • Increased mortality rate
  • Monitoring site:
    • Tympanic membrane: brain temperature
    • Nasopharyngeal mucosa: core temperature
    • Rectum: slow response in change to core temp
    • Esophagus

Chih-Min Liu

epidemiology
Epidemiology
  • 40-60% after volatile anesthetics
  • Young male adult, rare in elder (age impairs thermoregulatory control)
  • Length of anesthesia or surgery
  • Peri-op rewarming procedure: if not
  • Mild hypothermia
    • The more serious hypothermia, the higher the probability
  • Anesthetic used
    • Less common with propofol; more with halogenated agent, pentothal

Chih-Min Liu

pathophysiology
Pathophysiology
  • Consequence of postanesthetic shivering
    • Discomfort
    • Increased pain
    • IICP, IOP
    • O2 consumption (VO2): more 40 – 120%
    • Increased minute ventilation
    • Cardiac morbidity

Chih-Min Liu

pathophysiology6
Pathophysiology
  • Two types of postanesthetic shivering
    • Thermoregulated shivering
      • With cutaneous vasoconstriction, the response of hypothermia
      • Perioperative hypothermia
    • Non-thermoregulated shivering
      • Mechanism unknown
      • Postoperative pain related?

Chih-Min Liu

pathophysiology7
Pathophysiology
  • Origins of Postanesthetic Shivering
    • Perioperative hypothermia
    • Postoperative pain
    • Perioperative heat loss
    • Direct effect of certain anesthetics
    • Hypercapnia or respiratory alkalosis
    • The existence of pyogens
    • Hypoxia
    • Early recovery of spinal reflex activity
    • Sympathetic overactivity

Chih-Min Liu

perioperative hypothermia
Perioperative hypothermia
  • Phase I: 1st hour
    • Internal redistribution: from center to peripheral
  • Phase II: 2-4 hours
    • Heat loss: skin, viscera
  • Phase III:
    • Steady-state

Chih-Min Liu

pathophysiology9
Pathophysiology
  • Early recovery of spinal reflex activity
    • Residual effect of anesthetics on the inhibiting control exercised by supraspinal structure
    • Propofol in low concentration may have less effect on certain central structure such as the reticular formation, thus faster recovery of descending inhibiter control

Chih-Min Liu

temperature regulating system
Temperature-regulating system
  • Thermosensors
    • Skin to hypothalamus
  • Afferent pathway, integration area
    • Spinal cord
    • Modulate: NRM( serotonin), LS(NE)
    • Integration inputs: PO-AH
  • Efferent pathway
    • Central descending shivering pathway: PH
    • Multiple inputs>common efferent signal
    • Spinal αmotor neurons, axons

Chih-Min Liu

pathophysiology11
Pathophysiology
  • Human defenses to hypothermia:
    • Skin vasomotor activity
    • Nonshivering thermogenesis
      • Cell metabolic without mechanical work, Neonate
    • Shivering
    • Sweating
  • Shivering is the last-resort defense

Chih-Min Liu

pathophysiology12
Pathophysiology
  • Shivering
    • Several types
    • 4-8 Hz., waxing-and-waning pattern
  • Postanesthetic tremor
    • Thermoregulatory inhibition abruptly dissipates, thus increasing the shivering threshold toward normal
    • New, near-normal threshold activate shivering
  • Shivering like activity
    • Pain in post-op and labor female

Chih-Min Liu

prevention management
Prevention & Management
  • Perioperative Hypothermia Prevention
    • Limiting the effects of internal redistribution
      • Skin surface rewarming with forced-air warmer for 30 minutes
    • Reduce heat loss
      • Radiation from skin surface
      • Room temperature > 23oC if the op field is large
      • Cover the patient as much as possible
    • Intravenous fluid rewarming

Chih-Min Liu

prevention management14
Prevention & Management
  • Passive prevention is not enough
  • Active heat transfer
    • Cutaneous patch is the most efficient
    • Forced warm air better then…
    • Water circulation blankets
  • 1/3 cover of the cutaneous surface is enough
  • Under GA > vasodilatation > heat loss

Chih-Min Liu

prevention management15
Prevention & Management
  • Physical treatment
    • Shivering threshold:
      • skin 20%, core 80%
    • Raise temp to inhibit postoperative shivering:
      • skin 4oC = core 1oC
    • Radiation heat system
    • Forced air warmer:
      • reduce frequency and duration of shivering

Chih-Min Liu

prevention management16
Prevention & Management
  • Medical treatment
    • Opiates
    • Tramadol, Ketanserin, Nefopam and Ondensetron
    • α2-Adrenergic Agonists
    • Other drugs

Chih-Min Liu

opiates
Opiates
  • Meperidine
    • Demoral
    • Κ-opioid receptor
    • Shivering threshold
    • Vasoconstriction
    • Sweating
  • Others:
    • Pure μ-receptor agonists
    • Morphine, alfentanyl, fentanyl
  • Sites of action
    • PO-AH, dorsal raphe nucleus neurons, RMN, LS, and the spinal cord

Chih-Min Liu

meperidine demoral
Meperidine( Demoral)
  • Sweating
  • Vasoconstriction
  • Shivering threshold

Chih-Min Liu

tramadol ketanserin nefopam and ondensetron
Tramadol, Ketanserin, Nefopam and Ondensetron
  • The balance of Norepinephrine and serotonin(5-HT) in the PO-AH controls the body temperature set point
  • 5-HT induce hyperthermia; α2-Adrenergic Agonists (clonidine) reduce core temperature
  • Opposite modulatory inputs from NE and serotonergic neurons shifting the shivering threshold
  • All 4 drugs acts on the serotonin neuromediator
  • Encourage the inhibiting effect of serotonin on OP-AH

Chih-Min Liu

tramadol ketanserin nefopam and ondensetron20
Tramadol, Ketanserin, Nefopam and Ondensetron
  • Tramadol
    • Inhibits reuptake of 5-HT, NE, dopamine and facilitate 5-HT release
    • Site of action: Pons
    • Analgesic effect, non-opioid analgesic
    • 1 mg/kg for shivering, reduce threshold by 0.8oC
  • Nefopam
    • Inhibits reuptake of 5-HT, NE, dopamine and lower normal body temperature
    • Analgesic effect, 0.15mg/kg or 20mg
  • Ketanserin
    • Low efficacy
    • Antihypertensive effect, 5 HT2 antagonist, 10mg
  • Ondensetron
    • Antiemetic, 5 HT3 antagonist, 8mg

Chih-Min Liu

2 adrenergic agonists
α2-Adrenergic Agonists
  • Clonidine 75μg
    • lower the threshold of cutaneous vasoconstriction and shivering by 0.5oC
    • Bolus & perfusion:
    • At the end of op: 1.5 or 3μg/kg
    • Cardiac surgery: 200 to 300μg
  • Mechanism:
    • Central
    • Shivering centre is under inhibiting control of the preoptic anterior hypothalamic region
    • α2-Adrenergic Agonists probably strengthened it
  • Dexmedetomidine

Chih-Min Liu

other drugs
Other drugs
  • Other drugs
    • NMDA receptor antagonist:
      • Ketamine
      • Magnesium sulfate 30mg/kg
    • Methylphenidate 20mg
      • Analeptic agent, block reuptake of 5-HT
    • Physostigmine 0.04mg/kg
      • Central acting cholinesterase inhibitor
    • Doxapram 100mg or 1.5mg/kg
      • Respiratory stimulant, central action on pons
    • Recovery of the descending inhibitor control of the supraspinal effecting centers

Chih-Min Liu

conclusion
Conclusion
  • Hypothermia is associated with shivering and many complications, patient should be kept normothermia
  • Prevention of hypothermia consists of limiting heat loss and active rewarming system
  • Effective treatment of shivering will reduce metabolic heat production and must be accompanied by an effective active heating system.
  • Skin surface rewarming is less efficient then medical treatment with meperidine, tramadol, or, in certain situations, clonidine
  • All antishivering drugs except ketanserin have some analgesic properties in humans, suggested that pain and thermoregulation are tightly connected
  • No single structure or pathway is responsible for the shivering response

Chih-Min Liu